Attack of the Puppet People (1958)

Deranged doll-maker Mr. Franz is deathly afraid of being left alone, so he creates a machine that can shrink humans down to only a few inches tall. He soon accumulates a troupe of shrunken prisoners whom he forces to perform for him and keep him company. When he shrinks his secretary Sally and her fiance Bob, the pair decide against spending their days as pint-sized playthings and try to find a way to escape and re-enlarge themselves.